/*
 * Copyright 2007-2008 by Matthias Buch-Kromann <mbk.isv@cbs.dk>.
 * 
 * This file is part of the Open-source Dependency Toolkit (OSDT),
 * see http://code.google.com/p/open-source-dependency-toolkit. 
 * 
 * The OSDT is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License,
 * or (at your option) any later version.
 *
 * The OSDT is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the OSDT in the files COPYING and COPYING.LESSER. If
 * not, see http://www.gnu.org/licenses.
 */

package org.osdtsystem.functions;

import org.osdtsystem.graphs.GraphAccessor;
import org.osdtsystem.values.Location;
import org.osdtsystem.values.StringFeature;

/**
 * A function that returns the union of all out-edges for nodes in
 * the outnode list. 
 * @param <V> 
 * @author Matthias Buch-Kromann <mbk.isv@cbs.dk>
 */
public class FuncFeatureValue<V> extends AbstractSingletonFunction<V> {
    StringFeature feature;
    SingletonFunction<? extends Location> location;
    
    public FuncFeatureValue(Class<V> valueclass, String feature, 
                SingletonFunction<? extends Location> location) {
        super(location);
        this.feature = new StringFeature(feature);
        this.location = location;
    }

    @Override
    public V _singletonFunctionValue(LocalFunction<?, ?> caller, FunctionContext context,
            GraphAccessor accessor) {
        Location locus = location.singletonFunctionValue(caller, context, accessor);
        return (locus != null)
                ? (V) accessor.featureValue(caller, locus, feature)
                : null;
    }

    @Override
    void toStringBuilder(FunctionStringBuilder builder) {
        builder.addParameter("feat", feature);
        builder.addSubfunction("loc", location);
    }
}
